Method for the manufacture of an elastic mould for the forming of groundcovering elements

Abstract: The invention relates to a groundcovering element, consisting of a plurality of components (1) with links (2,3) in between, a method for the manufacture thereof and a method for the manufacture of a mould (24, 25, 26, 27, 29, 30). According to the invention it is provided that the links between the components are deformable and possibly flexible, resulting in a groundcovering element that is easy to lay, offers better possibilities of adjustment to various desired surfaces to be covered and is considerably more suitable for a more or less undulating terrain. In the method of manufacture, one steel mould part (34) cooperates with many rubber ones (31), so that with little investment a high production rate is obtained.

Description: The invention relates to a method for the manufacture of a mould for the application of the aforementioned method, which is constituted in that an elastic mould is made of a plurality of model elements in the desired mutual arrangement, that of same mould a cast is made of a curable material, that said cast is finished at the base until a desired bottom surface of the cast has been obtained, and that of same finished cast a final mould is made, in which, if need be, in the desired places slits are made in the walls of the final mould, which are suitable to accommodate deformable links. In applying said method, it is possible to form a plurality of final moulds of the finished cast, which naturally fall under the present invention as well. The invention also comprises the use of the mould for producing ground covering elements. Such a groundcovering element is known from the European patent specification EP-B-0 004 364. This known element consists of components, with rigid linking elements in between, as well as a mesh of thin threads accommodated in the bottom of the components and connecting them. The rigid linking elements ensure a sufficient bond between the components, so that larger elements comprising a plurality of components can be laid, which preferably happens mechanically. The link between the components can subsequently be broken by vibration, the mesh situated with said linking elements being cut as well. Also WO 93/07339, EP-A-0.004.364 and GB-A-2 212 195 show such groundcovering elements consisting of components, all of which have an inflexible link between the components and/or components touching each other. This leads to rigid links. Said known groundcovering elements, however, have for many applications a number of disadvantages. The first is that handling such an in principle inflexible element without the appropriate machines, such as is often the case for example when laying out gardens or parks, is difficult, especially because the various components are to rest evenly on the ground. A further disadvantage is that the elements are relatively difficult to adjust to certain designs of the desired groundcover, the more so because the links are not easily broken by hand. When, for example, it is desired to lay half a circle in front of a tree and, in case of a thicker tree, an inner row of elements can be omitted, it is hard work to break off and disengage such components one by one. It may also happen that in covering a surface it is desired that various elements interlock by alternately removing components at the edge. The most important difficulty in incorporating groundcovering elements as indicated hereinabove in gardens, however, is constituted in that it is very difficult to adjust them to a more or less undulating soil profile. The links between the ground covering elements can be part of a deformable mesh incorporated in a plurality of components. Such links preferably consist of one or more flexible cords or threads of a material not susceptible to rot. Suitable materials are here in particular plastics, which are virtually always rot resistant, are elastic in various degrees and can have a relatively high tensile strength, without wear and tear or fatigue fractures being to be expected. The height at which the links are situated is not of vital importance. In order, however, to obtain a sufficient flexibility in two directions, upward and downward so to speak, it is preferred that the links are attached at 2/3 to 1/3 of the height, measured from the bottom side of the components. In general, sufficient flexibility can be combined with sufficient shape stability of the elements by providing that the links between the side surfaces of the components have a length of 0.5 - 2 cm. Links in the form of cords and threads are preferably embedded in the material the components are made of, which is cured afterwards. An important application of the invention is constituted in the imitation of natural stone in a way as true to nature as possible. Not only can a cast be made of real pieces of natural stone, such as basalt, having the same shape and the typical fracture and relief properties of the natural stone, also the colour can be imitated by tinting the material to be cured. These materials are in general very colourfast and, although the result does not completely show the colour of the natural stone, the approximation is nevertheless a real surprise. In the invention the components may be pavement elements, but it is also possible to use them as a palisade or the like when covering slanting or vertical walls, or even to put them upright so as to form for example a flower box. In the latter case the components may have the shape of straight or curved pickets. The link usually need to be deformed only once. Consequently, the links need not be flexible, but being deformable is sufficient. Accordingly, the links can be of plastic or metal wire and in that case need to be bent only once for the desired adjustment to the surroundings. Such elements have been found to allow considerable savings of labour in the production. A more economical production, is obtained by the fact that the links are part of a flexible mesh incorporated in a plurality of components. As a result a considerable saving of labour can be obtained because with such a flexible mesh all links can be realized in one time. Such a mesh ensures a high degree of flexibility in a vertical plane, but also allows, albeit with some limitations, adjustment in horizontal direction of the mutual position of adjacent groundcovering elements. This is generally labour-saving and offers in particular the possibility of proceeding to a completely mechanised production of the elements according to invention. Furthermore, it can be provided that the links have a curved shape, such as a helical line, an undulating line or a U-bend. Thus a considerable adjustment of the mutual position of adjacent components is possible, whereas nonetheless relatively sturdy linking elements can be used. Said embodiment can especially be combined with the application of a flexible mesh, because, for instance when made of plastic, such a mesh provided with the indicated forms of the linking elements can be easily manufactured by means of injection moulding. In this manner also metal-wire meshes can be relatively simply manufactured from bent wires and the like. The linking elements may be of flexible plastic, but also of metal such as copper wire, steel wire (preferably stainless steel) or galvanised steel. Of course, a material not to be affected in the soil is preferred. In manufacturing the elements according to the invention it has been found favourable to carry this out in such manner that a curable material is poured into a mould with cavities that correspond with the desired components in mutual arrangement, and between the cavities walls, while at desired heights deformable elongated linking elements, passing the walls, are led through the cavities, that the curable material is at least partially cured and that subsequently the entirety is disengaged from the mould. Here it is preferably provided that in that walls slits have been made into which the linking elements are placed. It is now surprising that it is generally not difficult to cover the slits with loose small caps, but in particular that when using elastic moulding material is it possible to press the cords into the slits and that, with the removal of the moulded groundcovering element, it is easy to withdraw it from the mould in the direction of the slits. The invention will hereinafter be further explained, reference being made to the drawing, where: fig. 1 schematically shows a plan view of a part of the element according to the invention; fig. 2 shows a plan view of another embodiment of the invention; fig. 3 schematically shows a vertical cross-section of an element on a sloping ground; fig. 4 shows a plan view of an embodiment; fig. 5 is a cross-section of fig. 4 over the line V-V; fig. 6 is a front view of fig. 4; fig. 7 shows an elevational view of a number of elements according to fig. 4 in a practical application; fig. 8 shows another embodiment of a link; fig. 9 explains variations of fig. 8; fig. 10 shows another embodiment; and figs. 11a through 11d show four different stages of the manufacture of a mould for casting an element according to the invention; fig. 12 schematically shows a mould which makes automated production possible of groundcovering elements according to the invention; and fig. 13 shows a mould which enables a further automated method of production. In fig. 1 a plurality of components 1, shaped either at random or regularly, are connected by means of cords 2 in one direction and cords 3 in a direction perpendicular thereto. The cords are flexible and allow small displacements in a horizontal or vertical plane, small rotations in a horizontal plane and slightly larger ones in a vertical plane. Fig. 2 shows an embodiment preferably suitable for laying a groundcovering element in front of a tree. In case of a relatively thin tree the three rows 4, 5 and 6 are used, but with a thicker tree row 4 is omitted and the outside row is used. It is even possible to lay just one row, for example row 6. In the vertical cross-section, as shown in fig. 3, the elements 1 are connected by links indicated by 3. This offers the opportunity to follow the slopes in the terrain, which is a very important advantage, in particular for laying out gardens. Figs. 4 through 7 show an embodiment in which the components are in principle pickets. Hexagonal pickets 7, more or less corresponding with the shape of basalt, have been drawn in plan view in fig. 4 and in cross-section over the line V-V in fig. 5. The pickets have a flat bottom side 8 and at the upper side a bevel 9 with an upper surface 10. The pickets may be connected for example at three heights with cords 11, 12, 13, as can also be seen in the elevational view of fig. 6. Naturally, such pickets need not have a hexagonal diameter, but they may also be elliptic or circular, as well as diamond-shaped, etcetera. In fig. 7 an embodiment has been drawn, in which elements according to the invention, composed of pickets, are used to shield an earth wall increasing in height. In fig. 7 to the left there is a relatively small rise, which is shielded by short pickets of the element 14; subsequently there is a rise increasing in height with an element comprising pickets 15 increasing in height, and finally an element with relatively long pickets of equal height 16. Fig. 8 shows an embodiment with a link 3 by shape of a bendable wire, which has been bent up and down and consequently allows a considerable displacement in horizontal direction and a relatively wide angular displacement. Other examples of such a link have been drawn in figs. 9a through 9d. In fig. 9d not only is bending present in the plane of drawing, but also the portion 3' is hairpin-shaped, which makes great deformations possible. In fig. 10 a plan view has been drawn of a flower box or the like, constructed by means of pickets according to the invention. It has been observed that from flower boxes constructed accordingly, when filled with earth, no earth leaks out and can therefore be considered very satisfying flower boxes. In figs. 11a through 11d the subsequent steps have been represented to obtain a mould suitable for casting elements, the shape on the visible side entirely corresponding with those of the models chosen for that purpose. Fig. 11a shows such a model 17, for instance of natural stone. By 18 a mould has been indicated which has been fitted thereon and is made for example of elastic material that can be poured. In fig. 11b the mould 18 has been turned and in it an artificial element 19 has been cast. After same element has been taken from the mould, a base 20 may be added, which gives the upper side 19 a desired height above the ground surface 21 of the addition 20. Over a plurality of adjacent elements 19, 20 a mould 22 is sprayed, as is shown in fig. 11d. After said mould has been removed from said models, it may be used as a mould for elements according to the invention, often after cuts 23 have been made in the mould, on the bottom of which a link 3 is laid prior to filling up the various cavities of the mould. After this has happened and the poured material has been cured, the various elements may be removed by retiring them in the direction of the slits 23. It has been found that in case of a plastic material such a slit 23 may be a simple cut and, because said cut is located at the bottom side of the element to be cast, any irregularities at such cut are not of any importance. Nonetheless, these irregularities may be concealed by covering a cut. Moreover, when the elastic material is well chosen, hardly any irregularities at the cut occur. A method for the automated manufacture of the groundcovering elements in accordance with the invention will hereinafter be explained, reference being made to figs. 12 and 13. The mould, in which a groundcovering element according to the invention can be manufactured, has been schematically represented in fig. 12. Such mould has a bottom plate 38 which can be moved up and down by means of a power engine 39 not drawn in detail. The plate 38 may be adapted to the upper side of the respective component, as has schematically been indicated by the line 24. For the manufacture of simple rectangular components, such filling as indicated by the line 24 need not be applied. In the drawn embodiment the mould cavities for only two components have been indicated in cross-section. These have for instance an outer wall 25 made of steel and a partition wall 26. In same partition wall a cut 27 has been made where the link 28 is led through. A stamp 29 provided with an extrusion 30 that corresponds with the recess 27, is moved downward after the cavities between the walls 25 and 26 have been filled with curable material, so that no curable material forms a direct link between both components and the link 28 can be easily disengaged. The procedure when using the mould press according to fig. 12 is constituted in that, after the plate 38 has been moved downward, the mould cavities are filled with curable material, preferably relatively dry concrete mortar, and a mesh of linking elements 28 is accommodated. Naturally, it is also possible to fill up the mould first almost half way, then to accommodate the mesh and subsequently to complete the filling procedure. Then the stamp 29 is moved down and, after a possible short curing period, moved up again, whereupon the cast groundcovering element can be ejected due to the upward motion of the plate 38. This is preferably done by covering the mould with a receiving or curing plate and, after the stamp has been removed, by turning over the entirety and enabling the cast groundcovering element to cure. In fig. 13 a rubber plate has been indicated by 31, which has mould cavities 32 having the shape of the top of components, provided with partition walls 33. A plate 34 preferably of steel has holes 35 with in casting position vertical partition walls 36 that engage the partition walls 33. After laying down the rubber plate 31 with the cavities 32 turned upward, a mesh 37, for example made of plastic string, metal wire etcetera, is accommodated and subsequently the plate 34 is lowered. Then the cavities 32 and the openings 35 are filled with preferably rather firm concrete mortar. After vibration the plate 34 can be lifted fairly soon and removed for reuse with another plate 31. After a curing period of for example 24 hours, the element can be disengaged from the cavities 32, preferably after having been turned over. The procedure indicated hereinabove offers the possibility of using, against one single plate 34, a great quantity, for example 500 to 700, of considerably less expensive rubber plates 31, making a high production rate possible with a limited investment. In laying the groundcovering element, for example on a ground reinforced by a little cement, it is possible to adjust to a certain degree the mutual position of the components, curves in the vertical surface no longer presenting any difficulties either.

Claims: Method for the manufacture of an elastic mould (22) that is destined for the forming of ground covering elements (1), characterized in that it comprises at least the following steps: selection of one or more different elements (17) of natural stone, the manufacture of elastic moulds (18) of the elements (17) of natural stone, using the elastic moulds (18) of the elements (17) of natural stone to make a plurality of model elements (19), placing the model elements (19,20) in a predetermined arrangement in a flat mould, pouring a curable material over the arranged model elements (19,20), the curable material resulting in a final mould (22) of elastic material. Method according to claim 1, characterized in that the method also comprise the step of making slits (23) in the elastic material between adjacent cavities in the final mould (22), which slits (23) are to receive links (2,3) that connect the individual elements (1). Method according to claim 1-2, characterized in that the different model elements (19) are provided with a socket (20), as a result of which the model elements (19) have about the same height. Use of a mould (22) made by the method according claims 1-3 to make a ground covering element (1).

Inventors: BOEVE JAN ANTONIE, BOEVE, JAN ANTONIE, Boevé, Jan Antonie
Applicants: CARPETSTONES B V, CARPETSTONES B.V.
Application year: 1994
Main classification: E01C5
IPC codes: B28B7, E01C5, B28B23